In recent years, since miniaturization of electron devices, such as a transistor, progresses, and the size thereof has nano size, a new phenomenon called a quantum effect has been observed. Then, the development which aimed at achieving of ultra high-speed devices or new functional devices is advanced using such a quantum effect.
On the other hand, trials to perform large capacity communication, information processing, or imaging or measurement, etc. has been performed in such environment using the frequency region which is in particular called a THz band and of which frequency is from 0.1 THz (1011 Hz) to 10 THz. Such a frequency region is undeveloped frequency region between light and electromagnetic waves, and if a device which operates with this frequency band is achieved, there is expected many uses, such as measurement in various fields, e.g., physical characteristics, astronomy, living things, etc. in addition to the imaging, the large capacity communication, and the information processing mentioned above.
As a device for oscillating a high frequency electromagnetic wave at a frequency of the THz band, there is known a device having a structure for integrating a minute slot antenna on active devices, such as a transistor or a diode (for example, refer to Non Patent Literature 1).
On the other hand, there is also disclosed a THz oscillation device which can eliminate a leak from a slot transmission line over the whole oscillation frequency region and can oscillate a high-efficiency and high-output electromagnetic waves, even if it is the electromagnetic waves at a frequency band with the comparatively wide bandwidth oscillated from frequency variable oscillation devices (for example, refer to Patent Literature 1).
By the way, in conventionally, surface plasmon sensors using surface plasmon resonance (SPR) is known as a sensor for testing liquids, cells, etc.
The surface plasmon sensor is a sensor for measuring a dielectric constant of materials, e.g. liquids or cells on a metallic thin film, using the SPR, and is widely used for measurement of solution concentrations, and detection of protein or polymers, etc.